Trimming mechanism for sewing machines



Sept. 26, 1933 F M CARD l,928,587

' TRIMMING MECHANISM FOR SEWING-MACHINES Original Filed May- 28, 1930 3Sheets-Sheet l INVENTUR. 51mm; 7%, @WL BY sept. 26, 1933. F. M. cARD1,928,587s

TRIMMING MECHANISM FOR SEWING MACHINES Original Filed May 28, 1930 3Sheets-Sheet 2 INV EN TOR.

BY l

ATTORNEY Sept. 26, 1933. F. M. CARD 1,928,587'

TRIMMING' MECHANISM FOR SEWING MACHINES Original Filed May 28, 1930 3Sheets-Sheet 3 IN V EN TOR. fri/m m, CL4,

BY ATTORNEY Patented Sept.` 2926, 1933 r- No ivrnoimmsivrv Fon SEWING Y-MACHENES v 1 Y Frederic M. Card`, Bridgeport, Conn., assignor to TheSinger Manufacturing Company, Eliza- "beth, N. J., a corporation of NewHersey Original application"y May 28, 1930, Serial No.

456,380. Divided andy this application July 30,

1931,. serialNo. 554,028

6 anims. (Crim-$122) This inventionlrelates to improvements in trimmingmechanisms for sewing machines and more particularly in trimmingmechanisms of the type adapted to trim the marginal portions ofmavterials upturned in a presser-foot slot in advance of the pointofseam formation.

The primary object of ythe present invention is to providefortrimmingthe upturned fabricmargins at a substantially constantdistance above the sewing machine work-support in order to insurel amore uniform relationship of the trimmed margins in the stitched seam,whether said margins are abutting or slightly overlappingy in said seam.This object is accomplished by. constructing the trimming mechanism soas to be unresponsiveto movements of the sewing/machine presser-foot dueto slight variations in the thicknesses of the materials, but so as tobe capable of yielding to bulky portions rof theV work, such ascross-seams, and also so designed as to be shifted when the presser-footis raised fo f insertion and removal ofV work. c c

The foregoing and other objectsand advantages in View, togetherwith'means whereby the same may be carried into effect, will best beunderstood from the following description of a preferred embodiment ofthe invention illustrated,

in the accompanying drawings, in which:

Fig. 1 is a longitudinal section, partlyfin front elevation, of a sewing`machine containing the present improvement. Fig. 2` is a part front endelevation and part section, of the sewing machine with the upper portionof the bracketarm omitted. Fig. 3 is a rsectional view substantially onthe line 3-3 of Fig. 2. Fig. 4 isa view in side elevation, partlyinsection, ofthe presser-- foot, including asectional view of thethroatplate and feed-dogs. Fig. 5 is a rear side elevation, partly insection,of the presser-foot and i trimming mechanism. Fig. 6 is a topplan view of the presser-foot work-engaging plates, omitting the guardblocksandthe'auxiliary foot. Fig. 7 isa sectional View of the machinebracketarm, substantially on the-line 7-7 of Fig. 1. Fig. 8 representsperspective'views, partly in section, of the presser-foot andthesupporting bracket thereof, one of the foot-plates being shown indotted lines.

This vapplication is a divisionof my prior paty ent application SerialNo- 456,380, led May 28, 1930, to which prior application reference maybe had for a more complete disclosure of Athe sewingfmachine in whichthe present improvements have been embodied.y y

Referring to the drawingsthe sewing lmachine is shown kas having a framecomprising a bedplate 1 from one end of whichrises a tubular,supporting, base 2 for thestandard 3 of a tubular `bracket-arm 4, ,whichoverhangs thebed-plate 1 and terminates in a head 5,. Rising from thebed-plate 1, below the bracket-arm head 5,` is aV tubularwork-supporting post. "6 having a hinged closure-plate 7. Suitablysecured upon `the upper end of the post 6 is a throat-plate 8 providedwith a needle-slot 9 and. suitable feed-slots for feed-dogs 10 and `11whichfmay be operated rin any appropriate manner to advance the workupon the throat-plate. The throat-plate 8 preferably has a rigid`fabric-margin l'supporting member 12 in front vof the needle-slot 9,said member having a crest 13. f l f Y J ournaled for'rotation insuitable ,bearings providedin the bracket-'arm 4 isv a vmain actuatingshaft 14, carrying at its outer end a driving 'pulleyu 15 and at itsopposite end a crank-disk 16. This crank-disk. serves to actuate in theusual manner i a linkl'? operatively connected with a verticallydisposed needle-bar 18 journaled Ifor endwise reci'procation4 in alined.bearing apertures prop connected with the frame 19 hasat its oppositeend a split strap 22 embracing an eccentric *231;

The eccentric 23 is adjustably secured upon var shaft 24r disposed belowand crosswise of the,

main-shaft 14, which latter has gear connections with the transverseshaft 240i a character such that said shaft 24 rotates at one-half thespeed of rotation ofV the main-shaft. The needle-bar 18.A

effect the production of zigzag stitches.

Cooperating with the needle 25, below the throat-plate, is a loop-taker26 which in the prescarries at its lower end a needle 25, which throughY ent machine is of the rotary-hook type and car-` l ries a mass ofunderthread around which the `needle-thread loops are cast in theformation of lock-stitches. The actuating mechanism for the `loop-taker26 may be of any suitable character,

that embodied in the present machine being substantially the same asdisclosed in myhprior Patent No.,1,7z9,994, ceti, 1929..

Opposed to the feed-dogs 10, 11 is a presserfoot carried by a mainpresser-bar 27 guided for vertically directed endwise movements insuitable bearings provided inthe bracket-arm head 5. rlhis mainpresser-bar is yieldingly depressed by the usual spring (not shown) andmay be raised and lowered by any manually operated means commonlyemployed for this purpose. Upon the lower end of the presser-bar 27 issecured by a screw 28 a presser-foot supporting bracket 29, having inits front face a rectangular recess 30 with vertically disposed sidewalls. Snugly fitted in the recess 30 and secured therein by a screw 31is the vertically disposed, flattened shank 32 of the presser-foot, thisconstruction providing not only for ready removal of the presser-footfrom the machine but also for accurately attaching it to thepresser-bar. Projecting horizontally forward from the shank 32 arevertically spaced guide-members 33 provided with vertically alinedapertures in which are slidingly disposed the vertically directedauxiliary presser-bars 34 and 35. The lower ends of these auxiliary barscarry horizontally disposed shoes 36 and 37 entering the channeled heels38 and 39 of presser-foot plates 40 and 41, which respectively terminatein upturned toes 42 and 43 and are pivotally mounted upon the shoes 36,37 by horizontally disposed pivot pins, as 44, passing through thespaced members of the U-shaped heels in a direction crosswise oi theline of feed.

The foot-plates 40, 41 are yieldingly depressed independently of eachother by springs 45 and 46 coiled about the auxiliary presser-bars 34,35, said springs beingv interposed between the upper guide-member 33 ofthe presser-foot shank and collars 47 and 48 adjustably secured upon thebars 34, 35 to yieldingly rest upon the lower guide-member 33 andthereby limit the downward movement of the foot-plates 40, 41. Thecollars 47, 48 each have adepending guide-nn 49 slidingly disposed in asuitable guide-slot in the lower guide-member 33, whereby the bars 34,35 are confined to vertically directed movements.

The foot-plates 49, 41 are spaced from each other beginning from thetoes 42, 43 thereof to form a fabric-margin slot 50 which terminates ata point directly in front of the needle path, at which point theadjacent edges of the foot-plates curve inwardly into abutting relationto together form a split guide-web 51 which serves to deflect under thepresser-foot the upwardly directed fabric margins passing through theslot50. The

, guide-web 51 which also terminates in front of the `needle-path iscomparatively narrow in the 'formation to provide a needle-slot 53 inthe presser-foot. The auxiliary foot 52 is preferably rigidly carried bya shouldered guide-bar 54 of which the lower portion is slidinglydisposed in a p vertically directed aperture provided in a guideblock 55upon the presser-foot shank 32. The reduced upper end of the guide-bar54 is disposed within a screw-bushing-E adjustably threaded into theupper side of the guide-block 55, a spring 57 coiled about the reducedportion of the guidebar being interposed between the bushing 56 and theshoulder of the guide-bai'. The foot 52 has an upturned heel 58 whichoverlies a bent stopplate 59 secured by a screw 60 upon the rear side ofthe presser-foot shank 32, whereby downward movement of the foot 52under the action of the spring 57 is limited. It will be observed thatthe crest 13 of the fabric-margin supporting member 12 upon thethroat-plate rises substantially centrally of the presser-foot slot 50and that it is in alinement with the auxiliary foot 52.

The machine is provided with a mechanism for trimming the upturnedabric-margins passing through the presser-foot slot 50, said mechanismin the present instance including a horizontally disposed ledger-blade61 and a horizontally vibratory cutting-blade 62 resting upon theledger-blade, the cutting edges of said blades meeting in shearingrelationship directly above the foot slot 50 and in advance of theguideweb 51. v

rIhe ledger-blade 61A is rigidly clamped in a split head 63 of a collarsuitably secured upon the lower end of a vertically slidable rod 65journaled in spaced lugs 66 formed on an auxiilary bracket 67 secured byscrews as 68, upon a primary bracket 69 xed by screws, as 70, upon therear side of the machine head 5. The rod 65 is restrained againstoscillation about its longitudinal axis by a forked guide-collar 71adjustably carried by said rod and embracing a guide-rib "I2 on theauxiliary bracket 67. Underlying the collar 71 is a lip 73 projectinglaterally from a stopmember 74 secured for vertical adjustment upon thepresser-foot supporting bracket 29, The stop-member limits the downwardmovement of the red 65, the adjustment being preferably such that theledger-blade clcars the presser-foot plate 40 a suicient distance toallow for slight rocking movements of said foot-plate 40 about itspivotal support while riding uneven portions of the work. Thestop-member 74 also functions to raise the trimmer-blades when thepresser-foot is raised for insertion and removal of work. It will beobserved that the described construction furthermore provides foradjustably raising and lowering the trimming position with respect tothe work-support.

The cutting-blade 62 is rigidly clamped in a holder-collar 75 carried bya rod '76 slidably disposed in vertically alined apertures provided inspaced lugs 77, projecting forwardly from a rockarm 78. A spring 79coiled about the rod '76 is interposed between the upper of the lugs 77and a forked guide-collar 89 adjustably secured upon the rod above thelower lug 77, whereby the cutting-blade 62 is ,yieldingly urged intoengagement with the ledger-blade 6l which it overlies. The rock-arm 78has a split hub 81 clamped by a screw 82 upon a sleeve 83 journaled foroscillatory movements upon a vertically disposed ful- Crum-pin 84 xed invertically spaced bearinglugs, as 85, upon the primary bracket 69.Projecting laterally from the upper end of the sleeve 83 is an arm 86connected by an extensible link 87 with an arm 88 depending from one endof a horizontally disposed rock-shaft 89 journaled in a bracket 90suitably secured to the underside of the machine bracket-arm 4. Theother end of the rock-shaft 89 carries a crank-arm 91 pivotallyconnected with a pit-man 92 having a strap embracing an eccentric 93upon the main shaft 14. It will be observed that the ledger-blade 61 andits supporting means can be removed from the machine independently ofthe other bladesupporting means by detaching the auxiliary bracket 67'fromi the machine lli racl ;et-arr.fi, and that the entiretrimmer-blade supporting mechanism can be removed as a unit fromthemachine `by detaching'the primary bracket 69: f

. supports during the passage oi the wort: without aecting the trimmingposition.` The side face 98 of the guard-block 95 adjacent thelslot 50is gradually kcurved towards its rearward end to extend across said slot59 and merge with the rearward wall of a slot 99 formed in theguardblock 94, whereby the Vtrimmed-od portion of the work is divertedlaterally out of the seamline. Conforming with the diverting-surfacecurvature of said blocks and disposed directly thereabove in itsoperative positionso as to cooperate with said surface in deilecting thetrimmed-oil, fabric margins, is a diverter-blade 100 having its shank101 bent toclosely embrace the ledger-blade carrying collar. The ,curvedshank 101 of the diverter-blade has ahorizontally elongated slot` 102entered by the stop-screw 103 threaded into said collar and passingthrough a friction washer V194. This construction provides simplesupporting means for the diverter-blade, permitting the blade to bereadily swung intoand out of operative position. Because the function ofdiverter-r .blades of this character is well known, the drawingsshow theblade as swung into its ineiiective position to more yclearly illustratethe mechanism in part obscured by the blade in its operative position.

In order to join abricplies by a butt seam, the marginal portions oisuch plies upon the work-supporting post are directed upwardly to passthrough the presser-foot slot 59, whereupon the shearing elements 61, 62trim said margins and the trimmed-oir surplus is directed laterally outof the path of the needle yby the merging diverting surfaces of theguard-blocks 94, r95, aided by the diverter-blade 109. The trimmed- Lorfmargins oi the plies are. then forced downwardly into abutting relationby the presser-foot.

guide-web 5l duringthe advance of the workv by the feeding mechanism. i

The abutting fabric plies are joined by a Zigzag-stitch seam formedbythe 'verticallyrecip- 'rocating and laterally vibrating needle 25 inconjunction with the loop-taker mechanism beneath the throat-plate. Thepresser-foot plates 49, 41 are each capable oi riding `uneven portionslof the Work by reason of their pivotal and bodily yielding support uponthe presser-foot body and can readily adapt themselves to differences inthicknesses of the fabric plies being joined. The

auxiliary foot 52 rides the'seam formed and, as

usual, opposes aportion of the feed-dog in the absence of work toyassist in chaining-oil.

. Having thus set forth thenature ofthe invention, what I claim hereinis:-

` 1. A sewing machine comprising, in combination, stitch-formingmechanism including a reciprocatory needle, a work-support, work-feedingmechanism, v`a presser-footyieldingly opposed to the work-support havingspaced work-engaging foot-plates between which upturned marginalportions oi material are, adapted to pass, a `trimming mechanismincluding cooperating shearing tion, stitch-forming.mechanism includingareciprocatory needle,J afwork-support, work-feeding mechanism, apresser-bar, a presser-foot' carp ried by said presser-bar havingadjacent kioctplates spaced at the forward end thereof toprovide'betweenthem a slot adapted to receive'the upturned marginalportionsy of material, supporting means for said foot-plates upon thepresser-bai providing for yielding movements lof the foot-platesindependently or" each other in a direction away from the work-support,a trimming mechanism including cooperating shearing elements disposedkto trim said upturned marginal portions of material, means independentof the presser-foot for yieldingly depressing said shearing elementstoward the work-support, and means movable with said presser-bar actingto limit the downward movement of said shearing elements to normallyclear said foot-plates.

3. A sewing machine comprising, in combination, stitch-forming mechanismincluding a reciprocatory needle, a work-support, work-feedingmechanism, a presser-foot having adjacent work-engaging root-platesproviding between them a fabric-margin receiving slot in advance or nthe needle, supporting means for said foot-plates dependent or' thepresser-root for yieldingly de- 120.

pressing said shearing elements towardthe worksupp'ort, and means actingto limit the downward movement of said shearing elements to normallyclear said foot-plates. f

4. A sewing machine comprising, in combination, stitch-forming mechanismincluding a reciprccatory needle, a work-support, work-feedingmechanism,a presser-foot having adjacent foot-plates spaced at the forward endthereof to provide between them a slot adapted to receive the upturnedmarginal portions of material, supporting means for said foot-plates,providing for yielding movements thereof independently of each other ina direction away from the work-support, a trimming mechanism includingcooperating shearing elements disposed above and normally clearing thefoot-plates to trim said. upturned marginal portions of material, andguard-blocks upon said foot-plates provided with shearing-elementclearance recesses and having abutting surfaces crossing saidpresser-foot slot in position to divert the trimmed-oir iabricmarginsfrom the path of the needle.

5. In a sewing machine, in combination, a work-support, a presser-footopposed to said work-support having spaced work-engaging portionsproviding a slot adapted to receive up-` turned marginal portions ofmaterial, 'a trim.- ming mechanism including a ledger-blade and amovable blade arranged in cooperating shearing relationship in positionto trim said upturned marginal portions of material, ledger-blade 'supporting means, a diverter-blade extending across said presser-foot slothaving'its shank bent into circular form to embrace the ledger-bladesupporting means whereby said diverter-blade may be, swung into and outof operative position, and means for limiting the movement of thediverterblade into operative position.

6. In a sewing machine, comprising, in combination, a frame including afixed Work-support and an overhanging bracket-arm, stitch-formingmechanism, Work-feeding mechanism, a presserfoot Opposed to theWork-support having spaced work-engaging toes between which upturnedmarginal portions of material are adapted to pass, a trimming mechanismincluding a ledger- FREDERIC M. CARD.

